Grate.



3 smu -sum 1.

WITNESSES I, M Q, 6

- ATTORNEY J. NICHOLSON.

GRATE.

APPLICATION FILED OCT. 28, 1012.

1 1 22,% l 6, Patented Dec. 22, 1914.

L L" i;

INVENTOR J. NICHOLSON.

GRATE.

APPLICATION FILED 001. 28. 1912.

Patented Dec. 22, 1914.

3 SHEETSSHEET 3.

WITNESSES yzoyw INVENTOR i'l'tJHN NICH'DLSON, OF CHICAGO, ILLINUIS, ASSIGNOR, BY DIRECT AND MJESN'E ASSIGN- trace conranm'or cease, itrirrors, a con.-

inseam.

specification of Letters Patent.

Patented Dee. $2, fetid.

hppttcatlon filed tlctoher shawls. herlal lilo. 75283027.

- To all whom it may concern:

Be it known that 1, Jonn l lrorronson, a.

citizen of. the United States, residing at ful Improvement in Grates to be Used in Connection with Forced-Draft Furnaces.

Devices of this character with which ll am familiar are subject to numerous objections among which might be noted that Stratified furnace conditions in one part of the furnace chamber which contains a large percentage ofdistilled volatile matter, while another part contains the product of rapid combustion and still another part will admit the major part of the air to pass through a nearly burnt out fuel bed and around the grates, the air not reaching a suiliciently high temperature to ignite the combustible gases, due to the fact that it is not forced through the hot part of the fire bed.

Other systems are confined to the use of screened coal and also to the use of noncalring coals or inthe event of the use of a cakin'g coal, there is a very considerable loss of unburnt carbon. Any accident results in the necessity to close down the entire plant to permit movement of the grates. The efficient operation of the grates is also er:- pensive. Underfeed and'other stokers are objectionable due to the fact that they are confined to the use of screenings or coal with a low percentage of ash, which will not fuse at a low temperature. They are liable to have their parts burnt out if the fuel bed burns low and they are also compelled to close down in case of accident. 'lhere is no provision for proper supp? and distribution of the incoming air. ollow grate bars which are designed to handle forced draft with which i am familiar have been subject to the objection that there is a constant danger of a leakage of air, due to the warping of the bars, and there is also the liability for them to become clogged with ash, owing to improper air distribution.

My invention has for its object to avoid the above objections and to rovide a grate which is designed to be used in connection with a closed ash pit and which will permit of the use in the furnace of a-large volume of air at a low pressure and to construct the same so as to prevent the possibility of the ashes at any tune (preventing the free passage of'the air auto provide an arrangement, which will efllect the distribution of the air to each bar and to eachoutlet in top of the grate so-that there will be no tendency for the air to pass through the thin portion of the fire; and has for its further object to provide means for preventing the leakage 0 air and to locate the said means so that it will not be effected by the fire; and has for its further object to form the openingsleading from the barsto the fireof such shape that a gyrating movement will be imparted tothc entering air, thereby insuring its coming .in contact with all of the surrounding coal; and has for its further obect to provide a construction which will efiectually preventva larger amount of the air from entering the furnace through openmgs between or around the ends or sides of the grate bars and to provide a grate bar, the area and intake of whose outlets, wiil'be in the same proportion for all lengths of grates.

My means of accomplishing the foregoing may be more readily understood by having reference to the accompanying drawings,v

which are hereunto annexed and are a part of this specification, in which:

Figure l is a longitudinal section of a part of a furnace, showing'my improvement being used in connection therewith. Fig. 2 is a top or Ian view of one of the bars. 1F ig. 3 is a side elevation, part of the side wall being broken away to show the interior construction. lFi 4;- is a cross section taken on line w-m in F1 .2. Fig. 5 is an enlarged fragmentary detail view, showing the means for imparting the gyrating motion to the incoming air prior to its entrance to the coals.

Sim lar reference numerals refer to similar parts throughout the entire description.

As shown in the drawings, the grate consists of a plurality of grate bars 1, which are provided with inwardly tapering side walls 2, which latter are provided with longitudinal flanges 3. When the bars are placed in position, an opening is formed which is to be filled with cement, as t, of suitable composition to resist heat. lit will be apparent that this body of cement located as it is so far below the fire and being constantly' in contact with the incomin cool air will not be injuriously afi'ected by t e actionof the heat, while any leakage of air between the grate bars is absolutely prevented. v

The side walls are tapered inwardly until till Eltl

ltd

they form a rectangular opening 5 for the admission of the air. This prevents the entrance of an excess of air into the rate bar, which is then permitted to expand into the termediate the tapered portion of the side walls and resting on the flanges, there being a narrow rectangular opening between the side walls, the top wall having a plurality space 6 from which it escapes through a; of jet openings so shaped as to impart a plurality of openings 7 whichare tapered so as to bring the air down to a jet. They are also radially oblique, thus imparting a gyrating movement as it enters the furnace, with the result'that it insures the incoming air reaching every part of the fire and also pigtards its passage through the bed of the It will be apparent from the foregoing that any ashes which may fall through the openings '1 will have an unobstructed passage down into the pit 8, and can not under any circumstances clog the openings.

This construction secures a perfect distribution of the air throughout the fire and a consequent increase in efliciency. 'Whereit is employed I am able to use any kind of coal and to greatly increase the eificiency of the furnace.

The operation of the device is as follows: The air will enterthe ash pit 8 through the opening 9 formed in the wall 10 of the furnac'e, as indicated by the arrows. enter the I ate bars through the opening 5 where it isez tpanded in the chamber 6, whence it passes out through the openings 7 into the furnace; the air having a constant rotary motion results in its being thoroughly heated and distributed throughout the entire fire bed with the desirable'result as above set out.

Having described my invention, what I regard as newand desire to secure by Letters Patent is Y r 1. In a forced draft furnace, a plurality of hollow grate bars having a top and end walls and downwardly and inwardly tapering side walls, the latter being provided'with outwardly extending longitudinalflanges, there being a narrow rectangular opening between the side walls, the top wall having a plurality of jet openings in the top wal so shaped as to im art a whirl to the air as it enters the fire 0x, for the purpose set forth, substantially as described.

2. In a forced draft furnace, a plurality of hollow grate bars having end walls and downwardly and inwardly tapering side walls,'the latter being wardly extendin longitudinal flanges, a filler of suitable eat resisting material inrovided with outwhirl to the air as it enters the fire box, for the purpose set forth, substantially as described.

3. A hollow grate bar for forced draft furnaces formed with a top and downwardly and inwardly tapering side, walls, said topwall having a plura ity'of slots therein arrangedin circular relation, and a plurality of openings extending in a radially oblique direction to said circular slots, whereby the air entering is caused to assume a gyrating motion, said radially oblique openings being located within said arc-shaped openings, the walls of the radially oblique openings being flared downwardly so as to cause the air to enter in a jet for the purpose set forth substantially as described.

4. In a forced draft furnace, a plurality of hollow -grate bars having a top and end walls and inwardly tapering side walls, the latter being provided with outwardly extending longitudinal flanges, a filler of suitable heat resisting material intermediate the tapered portion of the side walls. and resting on the flanges, there being a narrow rectangular opening between the side .walls, the top wall having a-plurality ofjet openings so shaped as to impart a WhlIl to the air as it'enters the fire box and means to protect said filler from excessive heat, for the purpose set forth, substantially as described.

5; A rectangular hollow grate bar for forced draft furnaces the top wall of which is provided with a series of openings, each serles being'arranged in circular relation and comprising a plurality of are shaped slots the walls of which flare downwardly and a plurality of radially obli ue slots arranged within said are shape slots, the walls of said slots flaring downwardly, said radially oblique slots operating to lmpart a gyrating motion to the entering a1r.

In witness whereof I have signed the foregoing specification.

JOHN NICHOLSON.

\Vitnesses:

K. Donner, C. M. Baumnrs'mn. 

